Two-stroke-cycle internal-combustion engine



Oct. 30, 1928. 1,689,834

1-1.; KREISSLE TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE Filed Aug. 9, 1926 e, 3000 dobo Z;1/ van/far:

Hermann krgz sslu imw Patented Oct. 30, 1928.

UNITED STATES esassr HERMANN KREISSLE, OF ANSBACH, GERMANY.

TWO-STROKE-CYCLE INTERNAL-COMBUSTION ENGINE.

Application filed August 9, 1926, Serial No.

The invention relates to a two-stroke cycle internal combustion engine, the working cylinder of which is scavenged and charged through ports provided in the cylinder wall.

The invention relates to a two cycle internal combustion engine, in which the working cylinder is scavenged'and charged by means of openings in the cylinder wall, and consists therein that the scavenging and charging is carried out by means of a closed chamber which will only hold an amount of air necessary for a single working stroke of the cylinder. The air charge which is brought into the chamber before the opening of the ports is compressed to the extent that its expansion exceeds the back pressure in the cylinder for the purpose of preventing the loss of air into the exhaust, particularly in machines having low speeds, such as machines for ships in which the ports are open longer than in other machines. In this way the pressure of the scavenging air can be increased without difficulty. The air which is brought to the scavenging and charging ports will be preferably compressed to a pressure which 'is above the normal exhaust pressure and the container can be made smaller the. higher the pressure in the air feeding system.

The drawing illustrates, diagrammatically, three typical embodiments of the invention in which Figure 1 is a longitudinal cross-section of a cylinder of the engine,

Fig. 2 is a similar view of a modified construction, and

Fig. 3 is a similar view of another modified form.

a is the cylinder, 6 the piston, and c the fuel admission opening of a two-stroke cycle internal combustion engine, the exhaust ports of which are denoted by d and the scavenging air ports by c. The scavenging is effected from the air inlet pipe fby the piston 6 uncovering the exhaust and scavenging ports towards the end of the working stroke, and covering them again at the beginning of the compression stroke. Instead of being, as heretofore, in direct communication with the air inlet pipe, the scavenging ports communicate with an intermediate chamber 9. into which the air is admitted through an opening h. The orifice is of such small dimensions that it allows just as much air to pass during the working cycle into the chambep g as will pass into the cylinder, expanding down 128,248. and in Germany September 5, 1925.

to the back pressure there, when the scavenging and exhaust ports are open. In order to allow this quantity of air to pass into the cylinder in the short time during which the scavenging portsare open, the scavenging ports are made correspondingly large. The chamber also must be dimensioned in accordance with the pressure of the air flowing into it, so that the quantity of air expanding into the cylinder is exactly suificient to expel into the exhaust piping the products of combustion which cannot flow out without assistance. The chamber is therefore made smaller, the higher the pressure in the air inlet pipe. The admission of air to the chamber is controlled by adjusting the movable valve z', so that, when the scavenging ports are uncovered, the air in the chamber does not expand to any greater extent than is needed to expel the gases of combustion into the exhaust pipe. In this way the pressure of the scavenging,air.can be increased without having to take into consideration any undesired escape of air into the exhaust pipe. Owing to the short duration of the scavenging operation, the air continuing to enter the chamber 9 meanwhile through the opening 72. is of such small amount as not in any way to impair the improvement manifested by the invention. Of course, the opening shown in the drawing could be replaced by a controlled closing device.

In the example illustrated in'Figure 2 combustion air, the pressure of which exceeds that of the scavenging air, may also be admitted to the working cylinder through the valve 70 and ports Z, without passing through the chamber 9. The valve is may be automatic or positively controlled.

In the embodiment shown in Figure 3, the charging ports for the combustion air are Situated in the upper part of the cylinder, in order to prolong the time available for charging and thus enable the charge to be further increased. 1

I claim:

1. A two-cycle engine comprising a working cylinder having exhaust, scavenging and intake ports in the walls thereof; a chamber associated with said cylinder by means of the scavenging ports, said chamber being of a size to receive a sufiicient amount of air to scavenge the cylinder; and an adjustable valve in said chamber for permitting the scavenging air to enter the chamber.

enters the c linder through the adjustable 5 valve after t 1e scavenging.

3. A two-cycle engine according to claim 1 in which the intake air is under a pressure higher than the scavenging air and air enters the cylinder through a eonlrol valve and through ports arranged above the firstnamed scavenging ports.

In testimony whereof I have allixed my signature.

HERMANN KREISSLE. 

